Many materials have a well-characterized refractive index, but these indices depend strongly upon the wavelength of light. Therefore, any numeric value for the index is meaningless unless the associated wavelength is specified.

There are also weaker dependencies on temperature, pressure/stress, et cetera, as well on precise material compositions (presence of dopants et cetera); for many materials and typical conditions, however, these variations are at the percent level or less. Thus, it is especially important to cite the source for an index measurement if precision is required.

In general, an index of refraction is a complex number with both a real and imaginary part, where the latter indicates the strength of absorption loss at a particular wavelength—thus, the imaginary part is sometimes called the extinction coefficient k. Such losses become particularly significant, for example, in metals at short (e.g. visible) wavelengths, and must be included in any description of the refractive index.

See also

• Sellmeier equation

External links

• International Association for the Properties of Water and Steam
• Filmetrics Corporation of San Diego, California, 2002
• Ioffe institute, Russian Federation
• Crystran, United Kingdom
• Jena University, Germany
• Hyperphysics list of refractive indices
• Luxpop: Index of refraction values and photonics calculations

Physics lists

טבלת מקדמי השבירה | Lijst van brekingsindices